Brain images obtained by imaging the brain may be used for making a diagnosis as to whether examined subjects have a disease involving brain atrophy (e.g., Alzheimer's disease, Lewy body dementia, olivopontocerebellar atrophy, or corticobasal degeneration) or as to how much the symptoms have developed. Brains have a tendency of being atrophied by aging, even for healthy people. Thus, it is necessary to differentiate atrophy caused by aging from atrophy caused by a disease, in order to distinguish diseases of the brain. Brain atrophy caused by aging is observed in the whole brain, whereas brain atrophy caused by a disease is observed in a specific part of the brain.
Conventional medical image processing apparatuses evaluate brain atrophy by comparing a standard brain generated on the basis of brain images of healthy people with a brain image of an examined subject.
However, such conventional medical image processing apparatuses perform a non-linear position alignment process by using the generic model called the standard brain. Thus, a problem arises where it is difficult to make a diagnosis accurately, depending on the level of precision of the position alignment process.